cur/cur-lib/cur/olly.rkt
William J. Bowman bf987cdb06
Better surface syntax. Closes #34
* Unified the surface syntax. There are no longer distinctions between
  single-arity and multi-arity function/function types.
* Removed case and case*, in favor of match, a single advanced pattern
  matching construct.
* Updated all libraries, tests and documentation to use these new syntax.
* Some work to provide improved error messages in surface syntax.
2016-01-18 14:14:05 -05:00

315 lines
13 KiB
Racket

#lang s-exp "cur.rkt"
;; Olly: The OTT-Like LibrarY
;; TODO: Automagically create a parser from bnf grammar
(require
"stdlib/sugar.rkt"
"stdlib/nat.rkt"
;; TODO: "real-"? More like "curnel-"
(only-in "cur.rkt" [#%app real-app] [elim real-elim] [forall real-forall] [lambda real-lambda]))
(provide
define-relation
define-language
Var
avar
var-equal?
generate-coq
;; private; exported for testing only
(for-syntax
coq-defns
output-latex-bnf
output-coq
new-name
fresh-name))
(begin-for-syntax
(define-syntax-class dash
(pattern x:id
#:fail-unless (regexp-match #rx"-+" (symbol->string (syntax-e #'x)))
"Invalid dash"))
(define-syntax-class decl (pattern (x:id (~datum :) t:id)))
;; TODO: Automatically infer decl ... by binding all free identifiers?
;; TODO: Automatically infer decl ... for meta-variables that are the
;; same as bnf grammar.
(define-syntax-class inferrence-rule
(pattern (d:decl ...
x*:expr ...
line:dash lab:id
(name:id y* ...))
#:with rule #'(lab : (-> d ... x* ... (name y* ...)))
;; TODO: convert meta-vars such as e1 to e_1
#:attr latex (format "\\inferrule~n{~a}~n{~a}"
(string-trim
(for/fold ([str ""])
([hyp (syntax->datum #'(x* ...))])
(format "~a~a \\+" str hyp))
" \\+"
#:left? #f)
(format "~a" (syntax->datum #'(name y* ...)))))))
(define-syntax (define-relation syn)
(syntax-parse syn
[(_ (n:id types* ...)
(~optional (~seq #:output-coq coq-file:str))
(~optional (~seq #:output-latex latex-file:str))
rules:inferrence-rule ...)
#:fail-unless (andmap (curry equal? (length (syntax->datum #'(types* ...))))
(map length (syntax->datum #'((rules.y* ...)
...))))
"Mismatch between relation declared and relation definition"
#:fail-unless (andmap (curry equal? (syntax->datum #'n))
(syntax->datum #'(rules.name ...)))
"Mismatch between relation declared name and result of inference rule"
(let ([output #`(data n : (-> types* ... Type) rules.rule ...)])
;; TODO: Pull this out into a separate function and test. Except
;; that might make using attritbutes more difficult.
(when (attribute latex-file)
(with-output-to-file (syntax->datum #'latex-file)
(thunk
(printf (format "\\fbox{$~a$}$~n$\\begin{mathpar}~n~a~n\\end{mathpar}$$"
(syntax->datum #'(n types* ...))
(string-trim
(for/fold ([str ""])
([rule (attribute rules.latex)])
(format "~a~a\\and~n" str rule))
"\\and"
#:left? #f))))
#:exists 'append))
#`(begin
#,@(if (attribute coq-file)
#`((generate-coq #:file coq-file #:exists
'append #,output))
#'())
#,output))]))
(begin-for-syntax
(require racket/syntax)
(define (new-name name . id*)
(apply format-id name (for/fold ([str "~a"])
([_ id*])
(string-append str "-~a")) name (map syntax->datum id*)))
(define (fresh-name id)
(datum->syntax id (gensym (syntax->datum id)))))
;; TODO: Oh, this is a mess. Rewrite it.
(begin-for-syntax
(define lang-name (make-parameter #'name))
(define nts (make-parameter (make-immutable-hash)))
(define-syntax-class nt
(pattern e:id #:fail-unless (hash-has-key? (nts) (syntax->datum #'e)) #f
#:attr name (hash-ref (nts) (syntax->datum #'e))
#:attr type (hash-ref (nts) (syntax->datum #'e))))
(define (flatten-args arg arg*)
(for/fold ([ls (syntax->list arg)])
([e (syntax->list arg*)])
(append ls (syntax->list e))))
(define-syntax-class (right-clause type)
#;(pattern (~datum var)
#:attr clause-context #`(#,(new-name (lang-name) #'var) :
(-> #,(hash-ref (nts) 'var) #,(hash-ref (nts) type)))
#:attr name #'var
#:attr arg-context #'(var))
(pattern e:nt
#:attr clause-context #`(#,(new-name #'e.name #'->
(hash-ref (nts) type)) :
(-> e.type #,(hash-ref (nts) type)))
#:attr name (fresh-name #'e.name)
#:attr arg-context #'(e.type))
(pattern x:id
#:attr clause-context #`(#,(new-name (lang-name) #'x) :
#,(hash-ref (nts) type))
#:attr name (new-name (lang-name) #'x)
#:attr arg-context #'())
(pattern ((~var e (right-clause type)) (~var e* (right-clause type)) ...)
#:attr name (fresh-name #'e.name)
#:attr clause-context #`(e.name : (-> #,@(flatten-args #'e.arg-context #'(e*.arg-context ...))
#,(hash-ref (nts) type)))
#:attr arg-context #`(#,@(flatten-args #'e.arg-context #'(e*.arg-context ...)))))
(define-syntax-class (right type)
(pattern ((~var r (right-clause type)) ...)
#:attr clause #'(r.clause-context ...)))
#;(define-syntax-class left
(pattern (type:id (nt*:id ...+))
#:do ))
(define-syntax-class nt-clauses
(pattern ((type:id (nt*:id ...+)
(~do (nts (for/fold ([ht (nts)])
([nt (syntax->datum #'(type nt* ...))])
(hash-set ht nt (new-name (lang-name) #'type)))))
(~datum ::=)
. (~var rhs* (right (syntax->datum #'type)))) ...)
#:with defs (with-syntax ([(name* ...)
(map (λ (x) (hash-ref (nts) x))
(syntax->datum #'(type ...)))])
#`((data name* : Type . rhs*.clause)
...)))))
(begin-for-syntax
;; TODO: More clever use of syntax-parse would enable something akin to what
;; define-relation is doing---having attributes that contain the latex
;; code for each clause.
;; TODO: convert meta-vars such as e1 to e_1
(define (output-latex-bnf vars clauses)
(format "$$\\begin{array}{lrrl}~n~a~n\\end{array}$$"
(for/fold ([str ""])
([clause (syntax->list clauses)])
(syntax-parse clause
#:datum-literals (::=)
[(type:id (nonterminal:id ...) ::= exprs ...)
(format "\\mbox{\\textit{~a}} & ~a & \\bnfdef & ~a\\\\~n"
(symbol->string (syntax->datum #'type))
(string-trim
(for/fold ([str ""])
([nt (syntax->datum #'(nonterminal ...))])
(format "~a~a," str nt))
","
#:left? #f)
(string-trim
(for/fold ([str ""])
([expr (syntax->datum #'(exprs ...))])
(format "~a~a \\bnfalt " str expr))
" \\bnfalt "
#:left? #f))]))))
(define (generate-latex-bnf file-name vars clauses)
(with-output-to-file file-name
(thunk (printf (output-latex-bnf vars clauses)))
#:exists 'append)))
;; TODO: For better error messages, add context, rename some of these patterns. e.g.
;; (type (meta-vars) ::= ?? )
;; TODO: Extend define-language with syntax such as ....
;; (term (e) ::= (e1 e2) ((lambda (x) e)
; #:latex "(\\lambda ,x. ,e)"))
(define-syntax (define-language syn)
(syntax-parse syn
[(_ name:id (~do (lang-name #'name))
(~do (nts (hash-set (make-immutable-hash) 'var #'Var)))
(~optional (~seq #:vars (x*:id ...)
(~do (nts (for/fold ([ht (nts)])
([v (syntax->datum #'(x* ...))])
(hash-set ht v (hash-ref ht 'var)))))))
(~optional (~seq #:output-coq coq-file:str))
(~optional (~seq #:output-latex latex-file:str))
. clause*:nt-clauses)
(let ([output #`(begin . clause*.defs)])
(when (attribute latex-file)
(generate-latex-bnf (syntax->datum #'latex-file) #'vars #'clause*))
#`(begin
#,@(if (attribute coq-file)
#`((generate-coq #:file coq-file #:exists 'append #,output))
#'())
#,output))]))
(data Var : Type (avar : (-> Nat Var)))
(define (var-equal? (v1 : Var) (v2 : Var))
(match v1
[(avar (n1 : Nat))
(match v2
[(avar (n2 : Nat))
(nat-equal? n1 n2)])]))
;; See stlc.rkt for examples
;; Generate Coq from Cur:
(begin-for-syntax
(define coq-defns (make-parameter ""))
(define (coq-lift-top-level str)
(coq-defns (format "~a~a~n" (coq-defns) str)))
;; TODO: OOps, type-infer doesn't return a cur term but a redex syntax bla
(define (constructor-args syn)
(syntax-parse (type-infer/syn syn)
#:datum-literals (Π :)
[(Π (x:id : t) body)
(cons #'x (constructor-args #'body))]
[_ null]))
(define (sanitize-id str)
(let ([replace-by `((: _) (- _))])
(for/fold ([str str])
([p replace-by])
(string-replace str (symbol->string (first p))
(symbol->string (second p))))))
(define (output-coq syn)
(syntax-parse (cur-expand syn #'define #'begin)
;; TODO: Need to add these to a literal set and export it
;; Or, maybe overwrite syntax-parse
#:literals (real-lambda real-forall data real-app real-elim define begin Type)
[(begin e ...)
(for/fold ([str ""])
([e (syntax->list #'(e ...))])
(format "~a~n" (output-coq e)))]
[(define name:id body)
(begin
(coq-lift-top-level
(format "Definition ~a := ~a.~n"
(output-coq #'name)
(output-coq #'body)))
"")]
[(define (name:id (x:id : t) ...) body)
(begin
(coq-lift-top-level
(format "Function ~a ~a := ~a.~n"
(output-coq #'name)
(for/fold ([str ""])
([n (syntax->list #'(x ...))]
[t (syntax->list #'(t ...))])
(format "~a(~a : ~a) " str (output-coq n) (output-coq t)))
(output-coq #'body)))
"")]
[(real-lambda ~! (x:id (~datum :) t) body:expr)
(format "(fun ~a : ~a => ~a)" (output-coq #'x) (output-coq #'t)
(output-coq #'body))]
[(real-forall ~! (x:id (~datum :) t) body:expr)
(format "(forall ~a : ~a, ~a)" (syntax-e #'x) (output-coq #'t)
(output-coq #'body))]
[(data ~! n:id (~datum :) t (x*:id (~datum :) t*) ...)
(begin
(coq-lift-top-level
(format "Inductive ~a : ~a :=~a."
(sanitize-id (format "~a" (syntax-e #'n)))
(output-coq #'t)
(for/fold ([strs ""])
([clause (syntax->list #'((x* : t*) ...))])
(syntax-parse clause
[(x (~datum :) t)
(format "~a~n| ~a : ~a" strs (syntax-e #'x)
(output-coq #'t))]))))
"")]
[(Type i) "Type"]
[(real-elim var t)
(format "~a_rect" (output-coq #'var))]
[(real-app e1 e2)
(format "(~a ~a)" (output-coq #'e1) (output-coq #'e2))]
[e:id (sanitize-id (format "~a" (syntax->datum #'e)))])))
(define-syntax (generate-coq syn)
(syntax-parse syn
[(_ (~optional (~seq #:file file))
(~optional (~seq #:exists flag)) body:expr)
(parameterize ([current-output-port (if (attribute file)
(open-output-file (syntax->datum #'file)
#:exists
(if (attribute flag)
;; TODO: AHH WHAT?
(eval (syntax->datum #'flag))
'error))
(current-output-port))]
[coq-defns ""])
(define output
(let ([body (output-coq #'body)])
(if (regexp-match "^\\s*$" body)
""
(format "Eval compute in ~a." body))))
(displayln (format "~a~a" (coq-defns) output))
#'(begin))]))